The next wave of people finds the downvoting excessive and upvote in response.
I think such people may be more harmful to the voting system than the usual vote manipulation.
Your vote should express whether you want to see more of something or less of something on LessWrong. Not to be used strategically to counter other people's votes. Then not only you don't contribute to the system, but also remove other people's contributions. What is it exactly you aim for? A webpage where no one will bother to downvote annoying content, because they will know someone else will immediately upvote it back?
You should upvote only those comments you would upvote regardless of their current score.
Some people think in terms of people behind the comments and not comments themselves. They think that downvotes cause sadness for a person who was downvoted and they use their upvote as a consolation, as an attempt to cheer a downvoted person up.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.